HARTFORD -- A federal grand jury is looking closely into the relationship between the former chief of staff for Connecticut's House Republicans, his private consulting company and two election campaign contractors he routinely recommended to GOP candidates.

Subpoenas from the U.S. Justice Department released Friday afternoon by House Minority Leader Lawrence F. Cafero Jr. indicate the grand jury is interested in the relationship between a political media company from Florida and another in Ohio, and George D. Gallo, 45, who resigned Thursday as Cafero's chief of staff.

Multiple sources said Friday they understood that Gallo routinely received "finder's fees" for providing clients, Hearst Connecticut Media has learned. They said that oftentimes the line between Gallo's firm and House campaign operations was blurred.

The subpoenas name Direct Mail Systems, of Clearwater, Fla., and King Strategic Communications, of Gahanna, Ohio, as part of the probe. Federal agents are looking into two GOP House political committees as well as Gallo and the companies' relationships with him. Republican sources say he suggested that both incumbents and challengers use the direct mail companies for their media campaigns.

Direct Mail Systems, a major supplier of Republican campaign materials throughout the country, did not return requests for comment.

Joe King, president of the suburban Columbus media company he founded, said in a statement Friday that his firm is in the clear.

"While none of the issues raised involve our company, we understand that authorities often need incidental data to help them do their job," King said. "We will, of course, cooperate. We're proud of the all the work we do and we always operate in a legal, ethical and above-board manner."

Both companies advertise as full-service political consultants and cite their experience with national GOP figures. They develop and deliver campaign messages across several platforms, including postal mailings, palm cards and fund-raising literature.

As chief of staff for House Republicans, a key part of George Gallo's job is to create a unified political message for all candidates.

William Bloss, a Bridgeport-based criminal defense lawyer with political campaign expertise, said Friday that the FBI seems focused on whether there were kickbacks from the companies to Gallo or his company, and the possibility of Gallo steering campaign media contracts of House candidates.

Potential federal laws at risk include wire fraud, so-called theft of honest services fraud and income tax evasion, Bloss said in an interview and follow-up emails.

"There's nothing wrong with using a printing company in Florida, by itself," Bloss said, "presuming everything is reported accurately. The federal fraud statute applies, at a minimum, to public or private employees who take kickbacks or bribes. That seems to be what the FBI is exploring here."

The release of the subpoenas to Capitol reporters came two days after federal agents visited Republican House offices in the Legislative Office Building, interviewed Gallo and spoke to about 10 Republican lawmakers, according to sources.

Gallo resigned Thursday, admitting that he was a subject of interest in the federal investigation. Subpoenas indicate that Special Agent Matthew McPhillips is leading the probe from the grand jury, which is sitting in New Haven.

Cafero declined comment Friday on the latest apparent scandal to taint state government.

During the last federal probe, an FBI sting targeted Cafero's New Friends PAC, but $1,000 presented to Cafero was quickly returned after former Speaker of the House Christopher G. Donovan's finance director was arrested for taking illegal contributions. Donovan, who maintained his innocence, lost the 2012 Democratic primary for the 5th Congressional District, but was recently told by federal authorities he is no longer a target of investigators.

Deputy House Minority Leader Vincent Candelora, R-North Branford, said in a phone interview Friday night that the investigation and resignation "is an unfortunate distraction" from the Legislature's busy session that ends May 8.

Candelora called the resignation of Gallo, a former state GOP chairman, "a selfless" act.

"Since there were no public officials involved with this, we can now move forward with the important issues facing the state of Connecticut." He said he was not among the lawmakers interviewed by the FBI.

For even-year elections in the 151-member House, those who accept public financing can collect about $27,000 if they raise $5,000 in individual contributions no higher than $100.

Most House candidates, whose districts have populations of about 24,000, use their campaign kitties for lawn signs and direct mailings, such as the kind provided by King and Direct Mail.

Both firms have worked for dozens of Republican candidates, although Direct Mail has had more clients than King, according to SEEC records.

Sixth-term Rep. DebraLee Hovey, R-Monroe, who announced she will not seek re-election just hours after FBI agents visited the caucus on Wednesday, called her move a coincidence unrelated to the investigation. She said she was involved in legislative meetings that day and was unaware of the FBI's arrival.

Hovey recalled that she usually contracted her own media support during election season. But she added that leadership usually recommends a caucuswide election program. Other caucus members, who asked not to be identified because federal officials have requested they not comment, said Thursday and Friday they were happy with Direct Mail's work.

In 2008, Direct Mail Systems refunded Hovey about $1,500, an amount almost identical to checks she remitted to the state's public financing program, in two installments both before and after the 2008 election, according to the State Elections Enforcement Commission.

A request for comment was left Friday for Gallo's Hartford lawyer, Hubert Santos.

The most recent example of Gallo's sphere of influence that was cited by sources came last spring, when Republican newcomer Sam Belsito, of Tolland, was compelled to use the Clearwater, Fla., firm to produce direct mailers for his special election campaign for the state House.

Filings with the SEEC show that Belsito, who was victorious in the 53rd District election, spent $18,893 on direct mail materials produced by the company within a one-week span.

The lion's share of the funds spent by Belsito's campaign came from the publicly financed Citizens Election Program, which he tapped for $20,138.

Requests for comment from Belsito were left Friday with his aide at the Capitol, as well as at his tuxedo shop in Vernon.

Belsito's victory in the 53rd District -- a seat once held by Lt. Gov. Nancy Wyman, a Democrat -- was viewed as a watershed moment by the state Republican Party, which tried to distance itself from the unfolding scandal.

"The state party has no involvement whatsoever," said Jerry Labriola Jr., the state GOP chairman. "It's an ongoing investigation, which we are following."

Labriola, who was elected party boss in June 2011, declined to comment further.

The flow of money to Direct Mail Services Inc. started raising red flags in 2010, when Hearst Connecticut Media first reported that the firm earned $300,000 from GOP candidates for the General Assembly who snubbed in-state competitors.

At the time, Gallo defended the choice of vendor, which he told Hearst came about following an informal bidding process in which a number of Connecticut firms were considered.

"When it came right down to it, it came down to price. It's pure economics," said Gallo, who previously served as executive director and then chairman of the state GOP.

Gallo estimated that it would cost 5 percent to 8 percent more to do direct mailings if the party's slate of candidates used a vendor in Connecticut.

While the party doesn't put out a preferred list of vendors, Gallo said it does recommend Direct Mail Systems if a candidate asks for advice on where to go.

State Rep. Alfred Camillo, R-Greenwich, a recipient of taxpayer money for his campaigns, was one of the few members of his party to voice his misgivings over the practice at the time.

"That could have been $300,000 that could have been spent here," Camillo said in 2010. "I don't like it at all. I had requested that they use a Connecticut firm. The one or two firms that can do it here in Connecticut are priced well above competitors out of state."

Camillo spent about $9,000 on that election cycle on palm cards and direct mailers produced by the company, which later refunded him more than $4,000 that he said he decided not to spend on campaign literature and was returned to the state.

The three-term incumbent confirmed in an interview Friday that he was contacted by the FBI about the matter.

"They called me and the first thing they said to me was, `You're not a target of this investigation. But we're fact-finding.' I told them everything I knew and tried to aid their inquiry."

Camillo, who is expected to seek re-election in November, declined to comment further.

Though he did not accept public funding for his 2010 run for governor, which fell 6,500 votes short, Republican Tom Foley paid Direct Mail Systems nearly $20,000 to send out campaign literature.

"We, certainly, weren't being directed by anybody toward any vendors," Foley said Friday. "They're a nationally known firm."

Foley, who is seeking to avenge his narrow loss to Democrat Dannel P. Malloy in this year's gubernatorial race, said he used the firm to do one mailing.

"We didn't use very much direct mail in 2010," Foley said. "The results weren't very good, so we stopped using them."

Danbury Mayor Mark Boughton, a former state representative and two-time candidate for governor, said he has never used the firm to do campaign mailings.